RDF effort in Northern VA.

Michael Chisena ka2zev at yahoo.com
Sun Apr 20 14:45:34 CDT 2008


All,
  Took part in a little excitement today.
   
   
  This morning (Sunday) went to check the e mail and got this note from one of the key players on the 147.300 repeater. (Input 147.900)
   
   
  Snip
   
   
  
(The Bluemont Repeater on 147.300 is experiencing interference at this 
time. Wes (Trustee / owner)  and I (AK4EA Ms. Virginia) are attempting to locate the source of the carrier, and  we have reports of it being between S1 and S5 in the Herndon area. 
   
   
  If anyone who might have the time or equipment to help us track it down 
would join in, we are coordinating efforts on 145.210- 141.3 (K4QJZ, 
which is the Skywarn backup machine).

  
Un Snip..
   
   
  Anyhow I sent back I would give it a try.
   
   
  The 147.300 was locked up fairly tight and very few people could get to it. This repeater has a huge coverage area, roughly three states worth. So even a small stuck transmitter can put it into a world of hurt. 
   
   
  I grabbed my AOR 8200 scanner and the Scout Frequency counter.
   
   
  The scanner has a ‘bar graph’ for relative signal strength. Programmed in 147.900. It also has a thumb wheel for scrolling frequencies. Very handy for using ‘slope detection’ when one is near a transmitter.
   
   
  Scout frequency counter has a bar graph for when one get’s into the near field of the transmitter, you can get a fairly good reading when the regular receiver is swamped.
   
   
  My usual Sunday morning romp is to take the dogs with me to breakfast at the Dunken Donuts in Leesburg. Why Leesburg? The idea is to keep the ‘Police Pack Dodge’ from turning to junk by running it once a week and the dogs like the road trip. I didn’t think this 'search and find' errand would take too long.
   
   
  Little problem, I didn’t have any transmitters along for the ride. The control heads for the radios in the car are under my work bench waiting for updates, so all I had was the receiver and counter. Bad plan.
   
   
  When it was all said and done, it took too dam long.  
  I’m out of practice.
   
   
  Came back from Leesburg along the toll road to the RT 28 SB.
  Didn’t start getting a signal until I was near RT66 and RT28.
   
   
  At this point I’m using long rubber duck antennas on the AOR scanner.
  Went east on 29 and in about a mile lost the signal.
  U turned and came back. 
  About a mile in on 29 is where I got the false hot spot.
   
   
  That one kept me busy for a while in and out of neighborhoods. 
  At some point the signal strength never went about half way on the AOR. 
   
   
  Gave up and went further down the road.
   
   
  Went about another mile and a half west on 29 the signal got to the point where I was able to switch to the tiny rubber duck. Was getting solid signals.
   
   
  At this point someone passed me transmitting on 147.915, the frequency counter ‘caught’ and recorded that signal. I start to drive into and out of the developments in the area. 
   
   
  So I end up on one nice residential street and I start to get stronger signals, strong enough to do slope detection and antenna off testing. I see a house with a large motor home in the driveway. In it there is a car with a strange looking antenna about the right size for a 2m whip.
  I ask the owner of that home, he knows nothing.
   
   
  Another false lead.
   
   
  I look at the frequency counter, and it’s now showing 147.900 as the memory.
   
   
  Sunday morning is not the best time for mental processing.
  Then it dawned on me, I’ve passed the address the counter caught it and I didn’t. 
   
   
  Down the block about three houses,  back towards RT 29.
   
   
  This time the bar graph on the counter moves, and I pass a house, then the bar graph fades off.  Do a u turn and look at the home again, in the back of the home is a short Diamond style antenna that I can see from the road. At this point I’m getting a half scale on the counter, and the scanner may be so far off tune that it won’t hear the signal at all well.
   
   
  Grab the counter, get out of the car and walk up to the home.
   
   
  At the front door, the counters bar graph reads full scale.
   
   
  I politely knock, the lady of the home answers.
   
   
  I ask if a ham radio operator lives there, and she says yes, and goes to get him.
  I get invited in and meet the operator. (A brave move, I look more than a tad bohemian, hair, beard, and the camo jacket don't help.)
   
   
  I explain that I’m looking for a ‘stuck microphone’ and I think it’s coming from here, show him the counter with the FS gage pegged.
   
   
  He heads down stairs, and checks the shack, and a moment later, the gage reads zero.
   
   
  Seems he dropped the microphone and when it hit the floor, it stuck in transmit.
   
   
  Problem solved.
   
   
  Lessons learned.
   
   
  Set the radios “time out timers” on our radios! 
  A 90 or 120 second transmission is better than a 15 or 20 hour one.
   
   
  Take a cheaper to operate vehicle when looking for stray signals. 
  The police pack gets in local driving about 12 mpg. But it was very quick.
   
   
  Don’t bring the pug puppy along, he kept trying to chew the rubber duck antennas.
   
   
  That’s the news.
  Mike


"You are, what you do, when it counts"  
The Masso

"Gravity, the quickest way down"  
Mayor John Almafi

"You ever drop an egg, and on the floor you see it break? 

You go and get a mop so you can clean up your mistake.  

But did you ever stop to ponder why we know it's true? 

If you drop a broken egg you will not get an egg that's new?" 

MC Hawking
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